Research On The Synthesis Method And Application Of The Variable Topology Parallel Mechanism

The variable topology parallel mechanism is a series of parallel mechanisms, which have the similar configurations but different characteristics. The in-depth research on synthesis method for the variable topology parallel mechanism can help not only to discover more configurations, but also provide a theoretical basis to select adaptive configurations, optimize configurations and computer-aided design. This dissertation systematically deals with the basic definitions of variable topology parallel mechanism, especially the state variable topology parallel mechanism, and the genetic synthesis method of the variable topology parallel mechanism. The kinematics and dynamics performance before and after the topology of parallel mechanism changes are analyzed, and the application for the tire building drum is also discussed.Firstly, the mathematical definition and pertinence theory about the topology basis of the parallel mechanism, the topology basis graph, and the variable topology parallel mechanism are given based on the theory of the variable topology mechanism, which can further improve the theoretical system of the variable topology parallel mechanism. According to the topological structure parameters of the variable topology parallel mechanism, the topology changing way, topological description, topology and displacement output of single open-chain, and topology changing criterion of the variable topology parallel mechanism are studied, and the topology-state characteristics of the variable topology parallel mechanism is analyzed through taking a typical parallel mechanism for an example.Secondly, combining the topology theory, group theory with genetic theory, the correspondence between the topology parameters changing and genetic operation including selection, reproduction and mutation is further researched. The topology changing operations of parallel mechanism are analyzed. The genetic synthesis method and the kinematics, dynamics and decoupling analysis of the variable topology parallel mechanism are given. According to an example, the integrated process of genetic synthesis, the configuration and decoupling are also analyzed in each topological state.Thirdly, the topological analysis is given in several states of the folding process of the tire building drum. The variable topology parallel mechanism is applied to design the folding mechanism of the tire building drum, and the related patent is applied in accordance with innovative of variable topology parallel mechanism applied in the tire building drum. The configuration type of two chains and three chains mechanism is analyzed in detail, which can realize two sliding and one rotation movement. It is given the integrated process using the genetic synthesis method and the two chains and three chains parallel mechanism, which can approach to the output trajectories of tire building drum. The folding trajectory planning of the tire building drum is simulated numerically.Finally, the appropriate configuration is selected in the synthesized configuration above, and configuration optimization and kinematics analysis is taken based on the analysis of the kinematics requirements of tire building drum. And then, the accessory models and the virtual prototype are designed in UG software, and the simulation analysis and verification of kinematics and dynamics characteristics of variable topology parallel tire building drum are taken in ADAMS software.Through the above analysis and studies, the theoretical system of the variable topology parallel mechanism is improved, and in-depth understanding of the topology parameters affecting to the performance of mechanism is discussed, which benefits for the creative design and application of the variable topology parallel mechanism.